Aerobic exercise programs typically include the use of some type of dowel or stick to promote extension of various movements, and weights for development of strength and muscle tone. Dumbbells are the weights generally used, but exercise bars of various forms are known in the prior art.
U.S. Pat. Nos. 1,714,391 to McWhirter; 4,440,391 to Saenz et al; and 5,029,847 to Ross show different forms of collapsible exercise bars. They are only generally relevant, but they are the closest prior art that I know of.